Patent GB-673049-A (GB)
Title: Improvements in or relating to the method of producing hydrogen
IPC: C01B3/30
Filed: 1950-09-07
Abstract: Hydrogen is produced by circulating a hydrocarbon in gas phase, e.g. methane, ethane, propane, vaporized liquid hydrocarbons, or gases from cracking liquid or solid hydrocarbon materials such as coal tar pitch, and steam in concurrent intimate contact through a reaction zone containing strontium oxide, maintaining the reaction zone at 1500 DEG -2100 DEG F. and at least 1 atmospheric absolute, the amount of oxide being sufficient to absorb substantially all the <PICT:0673049/III/1> carbon dioxide produced, pressure being at least one atmospheric for the range 1500 DEG -1865 DEG F. and for the range 1865 DEG -2100 DEG F. being at least that given by the empirical relation p=1+4.9X10-2(t-1865), where t is the temperature, and recovering the gaseous product.  In a cyclic process using three reactors steam from 42 and methane from 44 in proportions 2 : 1 to 4 : 1 are mixed and fed by pipes 46, 54 downwardly through freshly regenerated preheating fixed bed of strontium oxide at 2100 DEG -2150 DEG F. on porous plate 38 in reactor 32.  Some reaction occurs and heat is liberated by the strontium oxide/carbon dioxide reaction, which establishes a temperature gradient of at least 100 DEG F. downwardly in the bed.  Gases pass thence by pipes 64, 66 upwardly through a fixed bed of strontium oxide on porous plate 40 in reactor 34, which has a temperature gradient already established by use of reactor 34 as a preheater in the preceding cycle, and hydrogen is withdrawn through pipe 78, cyclone 84, pipes 96, 102, and 98, through steam preheater 110 to produce. There should be at least 600 parts of strontium oxide per 100 parts of carbon in the methane, and it may include additional catalysts such as copper on silica gel; nickel, cobalt, or iron on a-alumina, fused magnesia, or silica gel; or nickel; or stainless steel chips; or the strontium oxide may be impregnated with aqueous nitrates.  The bed in reactor 30, which was used for hydrogen production in the preceding cycle is simultaneously being regenerated under fluidized conditions at atmospheric pressure and 2100 DEG -2150 DEG F. by burning producer gas entering at 150 with air entering at 162.  Waste flue gases are withdrawn through line 74, cyclone 80 and line 114, through a steam/methane feed preheater. The producer gas is obtained by passing coal from hopper 126 and steam from line 134 into reactor 138 while injecting air at 142; the producer gas is withdrawn through line 144 and cyclone 146 to line 150.  The pressure in reactors 32, 34 is controlled by valve 112 on line 98; optimum conditions are 1600 DEG -1900 DEG F. at 20-50 atmospheres.  The particle size of the strontium oxide in the beds should be say -20 to +200 mesh so that at a gas velocity of 0.02-0.2 ft./sec. in reactor 34 the bed is unfluidized and at a gas velocity of 1-3.5 ft./sec. in reactor 30 the bed is fluidized. The temperature is maintained in reactor 34 by the strontium oxide/carbon dioxide reaction, but additional heat may be supplied, if necessary, by external heating or by combustion of carbonaceous material.  An apparatus using a single reactor is also described.